delay.h
1.33 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
#ifndef _M68K_DELAY_H
#define _M68K_DELAY_H
#include <asm/param.h>
/*
* Copyright (C) 1994 Hamish Macdonald
*
* Delay routines, using a pre-computed "loops_per_jiffy" value.
*/
static inline void __delay(unsigned long loops)
{
__asm__ __volatile__ ("1: subql #1,%0; jcc 1b"
: "=d" (loops) : "0" (loops));
}
extern void __bad_udelay(void);
/*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
static inline void __const_udelay(unsigned long xloops)
{
unsigned long tmp;
__asm__ ("mulul %2,%0:%1"
: "=d" (xloops), "=d" (tmp)
: "d" (xloops), "1" (loops_per_jiffy));
__delay(xloops * HZ);
}
static inline void __udelay(unsigned long usecs)
{
__const_udelay(usecs * 4295); /* 2**32 / 1000000 */
}
#define udelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 4295)) : \
__udelay(n))
static inline unsigned long muldiv(unsigned long a, unsigned long b,
unsigned long c)
{
unsigned long tmp;
__asm__ ("mulul %2,%0:%1; divul %3,%0:%1"
: "=d" (tmp), "=d" (a)
: "d" (b), "d" (c), "1" (a));
return a;
}
#endif /* defined(_M68K_DELAY_H) */